.sk_bd ul li {
  float: left;
  overflow: hidden;
  margin-right: 13px;
  width: 290px;
  height: 460px;
  border: 1px solid transparent;
  border-bottom: 0px;
}
.sk_bd ul li:nth-child(4n) {
  margin-right: 0px;
}
.sk_bd ul li:hover {
  border: 1px solid #c81523;
}
